<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="https://unpkg.com/vue"></script>
    <script>
        window.onload = function () {
            Vue.component('child', {
                props: ['myMessage'],
                template: '<span>{{ myMessage }}</span>'
            })
            var data = {counter: 0}
            Vue.component('simple-counter', {
                template: '<button v-on:click="counter += 1">{{ counter }}</button>',

                data: function () {
                    return{
                        counter: 0
                    }
                }
            })
            var app4 = new Vue({
                el: '#example-2'
                ,data:{
                    parentMsg:''
                }
            })
        }
    </script>
</head>
<body>
<div id="example-2">
    <div>
        <input v-model="parentMsg">
        <br>
        <child v-bind:my-message="parentMsg"></child>
    </div>
    <simple-counter></simple-counter>
    <simple-counter></simple-counter>
    <simple-counter></simple-counter>
</div>
</body>
</html>